Hi guys,
I’m looking to buy several of these 40A rated solid state relays from Sparkfun, but had to pause when several forums warned of counterfeit relays… did the fine people at Sparkfun ever tear down a relay to see if the mofset was really rated at 40 amps? Seen some others that when you actually tear them down they are only rated for 25 amps.
BTW love the Sparkfun vibe, ever since I bought a hacked bluetooth rotary phone back in 2012… Awesome!
We’ve never torn one down to look, but I can say that we don’t get complaints of failed relays very often at all. 
Most of the failures we have seen have been because a heatsink wasn’t used in applications where the relay was under a heavy load.
Ok thank you for the reply, I’ll go ahead and order some. I can say this, I happen to have the EXACT same relay (by markings that is) from a project a few years ago. Sparkfun is the only suppliers I have found with exactly the same item. When I take it apart, it is fully potted, and you cannot remove the two screws that remove the heat sink on the back, and thus have no way to check the true rating. From my research, this is an indication that it’s not a knockoff, as the super cheap ones are not completely potted and you can get to the screws. you just pop off the cover under the label. Does not look like it comes off but a razor knife will get in the crack and it comes right off. Any issues, I’ll let you know…Thanks so much!